It is known to provide a seat restraint system such as a seat belt in a vehicle to restrain an occupant in a seat of the vehicle. In some vehicles, the seat restraint system may be a lap belt, a shoulder belt, or both. Typically, the lap belt and shoulder belt are connected together at one end. The seat restraint system includes a latch plate at the connected end. The seat restraint system also includes a buckle connected at one end by webbing or the like to vehicle structure. The buckle receives the latch plate to be buckled together. When the buckle and latch plate are buckled together, the seat restraint system restrains movement of the occupant to help protect the occupant during a collision.
Smart inflatable restraint systems need to know what is occupying a seat of the vehicle. Decisions on deployment of inflatable restraints depend on information supplied by sensors in the seat in determining weight of an object in the seat. When a child seat is placed in the seat and cinched down, the sensors may read a large mass instead of a child seat. With this condition, there will be high tension in the seat restraint system. Comfort studies have shown that no human occupant would wear their seat restraint that tight. With this information on seat restraint tension, the inflatable restraint system can decide on deployment of the inflatable restraint.
Currently, vehicle manufacturers and suppliers have developed seat belt tension or switch monitoring devices to supplement information of the inflatable restraint system. However, several vehicles have interior architectures that do not lend themselves to mounting the seat belt tension sensor on the outboard floorpan or seat frame, and the inboard seat belt buckle side is a preferred location for the seat belt tension sensor for some applications. However, packaging a separate seat belt buckle latch and seat belt tension sensor presents a cumbersome challenge for interior designers.
Therefore, it is desirable to sense latching of a buckle for a seat restraint of a seat restraint system of a vehicle. It is also desirable to sense tension in a seat restraint of a seat restraint system of a vehicle. It is further desirable to integrate the seat belt buckle, the buckle sensor, and the seat belt tension sensor into a single monolithic sensor module to simply packaging. Therefore, there is a need in the art for a seat restraint and buckle tension sensing assembly that meets these desires.